$ { \left[\begin{array}{rr}{2} & {-2} \\ {1} & {-2}\end{array}\right]+\left[\begin{array}{rr}{2} & {3} \\ {1} & {1}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{2}+{2} & {-2}+{3} \\ {1}+{1} & {-2}+{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{4} & {1} \\ {2} & {-1}\end{array}\right]}$